The present invention relates to filter systems for use within a storm water sewer for filtering sediment, stones and other foreign materials in order to limit the flow of such materials into the storm water sewer system. There have been many different forms of filter systems either constructed or proposed and which are positioned under the cast metal grate positioned on a grate frame at the top of the storm sewer inlet, for example, as disclosed in U.S. Pat. Nos. 1,310,055, 5,284,580, 5,575,925, 6,149,803, 6,666,974, 6,998,039, 7,094,338, 7,112,274 and Published PCT Application No. PCT/SE98/00409. It is desirable with any such filter system to be light weight and durable in construction, easy to install after the grate is removed from the supporting grate frame, convenient to remove collected sediment and other foreign materials, easy to remove the sediment from the filter media, relatively inexpensive in construction and be able to accommodate the many hundreds of different sizes and configurations of storm sewer inlets and their associated cast metal grates and supporting cast metal grate frames. While some of the filter systems disclosed in the above patents provide some of these features and advantages, none of the filter systems provide all of these features and advantages. Also, applicant has produced one-piece welded wire baskets lined with flexible fabric filter material as disclosed in applicant's U.S. Design Pat. No. 598,196, Pat. No. 600,324 and Pat. No. 604,800. However, these filter baskets were constructed for use under storm water sewer grates and supporting grate frames of specific size and configuration and do not provide all of the desirable features and advantages mentioned above.